I'm debating whether or not to take a free walking tour of New Town in August. Is there enough there to justify a 2.5 hour tour? Also, if I can only pick between the Scottish National Gallery and Scottish National Portrait Gallery, which is better? We will have already been to the National Museum and done a fairly thorough job of Old Town.
As well, are the Britannia and Arthur's Seat hike worth it (instead of New Town)? We will have already spent time hiking in Skye, etc.